A strong association between endometrial cancer and replacement estrogen use has been demonstrated. Given the widespread use of these drugs, the high relative risk involved and the rising incidence of endometrial cancer, the possibility of an epidemic of this disease cannot be overlooked by public health officials. However, currently evidence is lacking that these drugs are associated with advanced stage disease. In order to develop a control program, critical data are needed about the trend in histologically confirmed endometrial cancer and the possibile association of estrogen use with late stage disease. It must be determined whether risk declines after cessation of estrogen use. In order to be able to institute control programs we must know more about estrogen usage patterns, the characteristics of women who take estrogens and the attitudes of the physicians who prescribe them. This information will be obtained through a series of interrelated projects, including: A. Ascertainment of true incidence trends through histologic re-examination and re-staging of a sample over time of patients reported to the New York State Cancer Registry. B. A case-control epidemiologic study to determine if estrogen use is associated with advanced stages of endometrial cancer and if there is a fall-off of risk following termination of use. C. A general population survey of a representative sample of New York State women about use of estrogens, knowledge of endometrial cancer, physician visitation habits and market research questions. D. A survey of physicians regarding prescription and indications for estrogens and the use of estrogens and the use of endometrial cancer screening examinations. These data will be used to develop a program of health education and other cancer control activities designed for the prevention and early detection of endometrial cancer. Once this cancer program is instituted in New York State, the data will serve as a baseline for evaluating it.